Taking a guess here, but I'm guessing Gamagoori is saying something about how the moon is beautiful, before catching himself, hoping that Mako is too stupid too understand the Natsume Souseki reference?
The moon... is beautiful..AHH!!Mako knows about that.No good...!!But...Mankanshoku wouldn't know the meaning of those words.I unconsciously let that out of my mouth.
